Method and apparatus for acquiring images created by penetration of radioactive ray

ABSTRACT

Disclosed is an apparatus and method of acquiring images created by penetration of a radioactive ray. The apparatus includes a scintillator to generate a light signal in response to an irradiated radioactive ray, and to change an advancing direction of the generate light signal, a light receiving unit to receive the light signal whose advancing direction is changed, and a signal processing unit to convert the received light signal into an electrical signal, and acquire an image corresponding to the penetrated irradiated radioactive ray based on the converted electrical signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Korean PatentApplication No. 10-2008-0129968, filed on Dec. 19, 2008, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference.

BACKGROUND

1. Field

Exemplary embodiments relate to an apparatus and method of acquiringimages created by penetration of a radioactive ray, which may generate alight signal from an irradiated radioactive ray, and change an advancingdirection of the generated light signal to condense the generated lightsignal in a light receiving unit, thereby improving a quality of thepenetration images with respect to a target of inspection/examination.

2. Description of the Related Art

An X-ray may be a short wavelength-electromagnetic wave generated suchthat electron rays emitted from a cathode at a high speed are collidedwith a heavy metal, and the X-ray may have a fluorescent effect and anexcellent light transmissivity with respect to an object. Accordingly,the invisible X-ray may be changed to a visible ray, and may be used inphotographing on a photograph film. Also, the X-ray may photographchanges in a density, a thickness, and the like of a target ofinspection/examination (hereinafter inspection target) using aphenomenon that a part of the X-ray introduced to the inspection targetis absorbed in the inspection target resulting in attenuation of theX-ray. An excellent penetrating power of the X-ray with respect to anobject has gained an interest as a main feature of the X-ray since thetime of discovery of the X-ray, and applications of the penetratingpower of the X-ray have been attempted in medical/industrial fields suchas hair loss treatment, and the like. The X-ray has been more widelyutilized since Sir W. H. Bragg and his son Sir W. L. Bragg developed anX-ray diffraction method in 1913 through their analysis of a crystalstructure, and William Coolidge developed a thermionic X-ray tube(Coolidge X-ray tube) in 1913, which may increase/reduce an amount orpenetrating power of the X-ray. Thereafter, with a development inexperiments and laboratory equipments, the X-ray is able to detect amacroscopic internal structure of an object and a microscopic structureof atoms of a material.

By acquiring the X-ray introduced to the inspection target as images,which is one of outstanding characteristics of the X-ray, variousinspections/examinations with respect to the inspection target may beconducted.

The X-ray may be utilized for medical purposes in a chest X-ray,ultrasonography, computed tomography (CT), magnetic resonance imaging(MRI), and the like. The X-ray may also be utilized for industrialpurposes in internal inspection for a circuit element, facility ofequipments, a nondestructive inspection such as for water leakagedetecting, and the like.

Images created by penetration of the X-ray widely used in all industriesmay be inferior in terms of image efficiency, as compared withefficiency of the irradiated X-ray, despite their widespreadapplications. For example, there is a significant disadvantage of theX-ray efficiency in that only about 30% of the irradiated X-ray may bematerially used in acquiring images. Accordingly, there is a need for atechnique of acquiring images created by penetration of the X-ray, inwhich the X-ray is effectively received to acquire the images having arelatively higher contrast even using a relatively small amount ofexposure of the X-ray.

SUMMARY

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the disclosure.

According to an aspect of exemplary embodiments, there is provided anapparatus to acquire images created by penetration of a radioactive ray,the apparatus including: a scintillator to generate a light signal inresponse to an irradiated radioactive ray, and to change an advancingdirection of the generate light signal; a light receiving unit toreceive the light signal whose advancing direction is changed; and asignal processing unit to convert the received light signal into anelectrical signal, and acquire an image corresponding to the penetratedirradiated radioactive ray based on the converted electrical signal.

According to an aspect of exemplary embodiments, there is provided amethod of acquiring images created by penetration of a radioactive ray,the method including: receiving an irradiated radioactive ray;generating a light signal in response to the received radioactive ray;changing an advancing direction of the generated light signal; andreceiving the light signal whose advancing direction is changed toconvert the received light signal into an electrical signal; andacquiring an image corresponding to the irradiated radioactive ray basedon the converted electrical signal, wherein converting the receivedlight signal into the electrical signal and acquiring the image areperformed using at least one processor.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of exemplary embodiments will become apparentand more readily appreciated from the following description, taken inconjunction with the accompanying drawings of which:

FIG. 1 is a block diagram illustrating an apparatus of acquiring imagescreated by penetration of a radioactive ray according to an exemplaryembodiment;

FIGS. 2 to 4 illustrate examples in which an apparatus of acquiringimages created by penetration of a radioactive ray is applied accordingto an exemplary embodiment; and

FIG. 5 is a flowchart illustrating a method of acquiring images createdby penetration of a radioactive ray according to an exemplaryembodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to the like elements throughout. Exemplaryembodiments are described below to explain the present disclosure byreferring to the figures.

FIG. 1 is a block diagram illustrating an apparatus 100 of acquiringimages created by penetration of a radioactive ray according to anexemplary embodiment.

Referring to FIG. 1, the apparatus 100 according to the presentexemplary embodiment includes a scintillator 110, a light receiving unit120, and a signal processing unit 130.

The scintillator 110 may generate a light signal in response to anirradiated radioactive ray, and change an advancing direction of thegenerated light signal.

The radioactive ray used throughout the present specification may besignals generated when elements with a relatively large atomic weightsuch as uranium and plutonium are disintegrated into an unstable statedue to a heavy nucleus, and may be comprehended as including at leastone of alpha rays, beta rays, and X-rays.

The present exemplary embodiment may be applicable in a field whereimages created by penetration of the X-ray are acquired, and thus‘X-ray’ may be hereinafter used instead of using ‘radioactive ray’ forthe convenience of description.

The scintillator 110 may generate the light signal in response to anirradiated X-ray. Specifically, when the X-ray is irradiated to thescintillator 110, the scintillator 110 may excite atoms or moleculesthrough an interaction with constituent elements of the scintillator110, and also generate, as a light (light signal), an energy obtainedwhen the excited atoms or molecules return to an original state.

The scintillator 110 may be configured with elements having a highdensity, a high atomic number, and a large volume based on efficiency inradiation-variation, a light transmissivity, a time ofradiation-attenuation, and the like. The scintillator 110 according toan exemplary embodiment may be generated using at least one mediumincluding at least one of NaI(Tl), CsI(Tl), LiI(Eu), ZnS(Ag),anthracene, plastics, and a liquid.

Also, the scintillator 110 may change an advancing direction of thelight signal generated in response to the irradiated X-ray. Thescintillator 110 according to an exemplary embodiment may change theadvancing direction of the generated light signal to a direction of thelight receiving unit 120.

The light receiving unit 120 may sense a light signal, and receive lightsignals transmitted using a light receiving sensor such as a PIN diodeand the like. Accordingly, the scintillator 110 may change the advancingdirection of the generated light signal so that the generated lightsignal is condensed in the light receiving unit 120 to the maximumextent.

In order to condense the light signal in the light receiving unit 120 asmuch as possible, the scintillator 110 according to an exemplaryembodiment may change the advancing direction of the light signal to thedirection of the light receiving unit 120.

For example, a side surface of the scintillator 110, adjacent to thelight receiving unit 120, may be formed into a concave shape, so thatthe scintillator 110 changes the advancing direction of the light signalto the direction of the light receiving unit 120. In this exemplaryembodiment, the scintillator 110 may include a medium having a densitydifferent from a density of the surrounding air. Specifically, the lightsignal passing through the concave shape of the scintillator 110 may becondensed in the light receiving unit 120 by the concave shape, wherebyan amount of the light signal received by the light receiving unit 120may approach an amount of exposure of the initially irradiated X-ray.

Similarly, the scintillator 110 may include a medium having a densitydifferent from a density of the surrounding air, and a side surface ofthe scintillator 110, exposed to the irradiated X-ray, may be formedinto a convex shape.

According to an exemplary embodiment, the light receiving unit 120 maybe formed on any one side of the scintillator 110 that is different froma middle portion thereof based on an array of other elements. In thiscase, the concave shape of the scintillator 110 for light condensing maybe laterally asymmetrical with respect to a location of the lightreceiving unit 120. This will be hereinafter described in detail withreference to FIGS. 2 to 4.

For another example, the scintillator 110 may be formed of two mediumswith densities different from each other, and, due to a difference inthe densities of the two mediums, may change the advancing direction ofthe generated light signal. In this exemplary embodiment, the advancingdirection of the generated light signal may be changed to a directionwhere the light receiving unit 120 is located due the difference in thedensities.

For example, a medium collecting an initial X-ray to generate a lightsignal may be denoted as a first medium, and a medium changing theadvancing direction of the generated light signal may be denoted as asecond medium. The second medium may be formed into a concave shape asdescribed above. The second medium may be formed into any shape capableof changing the advancing direction of the generated light signal to thedirection of the light receiving unit 120 based on the difference in thedensities as well as the concave shape. In this exemplary embodiment, atleast one of a type of the first medium, a type of the second medium,and a shape of the second medium may be determined considering aproduction environment including costs, technologies, and the like.

When the light signal generated from the X-ray is condensed in the lightreceiving unit 120, the signal processing unit 130 may convert thecondensed light signal into an electrical signal, and acquire apenetration image of an inspection target corresponding to theirradiated X-ray based on the converted electrical signal.

The apparatus 100 of acquiring images created by penetration of aradioactive ray according to an exemplary embodiment may include aplurality of scintillators and a plurality of light receiving unitscorresponding to each of the plurality of scintillators, and the signalprocessing unit 130 may combine light signals collected by the pluralityof light receiving units to acquire the penetration image of theinspection target.

Consequently, the apparatus 100 according to the present exemplaryembodiment may condense, in the light receiving unit 120, a great partof the light signals generated by the scintillator 110, therebyacquiring a clear penetration image with a high contrast even using arelatively small amount of exposure.

Also, by using the apparatus 100 according to the present exemplaryembodiment, damage incurred by the inspection target due to theradioactive ray may be minimized, and costs of maintenance incurred dueto exposure may be reduced by the relatively small amount of exposure.

Hereinafter, exemplary embodiments of the apparatus 100 of acquiringimages created by penetration of a radioactive ray described in FIG. 1will be described in detail.

FIGS. 2 to 4 illustrate examples in which an apparatus 300 of acquiringimages created by penetration of a radioactive ray is applied accordingto exemplary embodiments.

Referring to FIG. 2, an irradiated X-ray 201 may enter a side of ascintillator 202, and the entered X-ray may be converted into a lightsignal 204 in the scintillator 202. Converting the irradiatedradioactive ray into the light signal may be a general technique of thescintillator, and thus detailed descriptions thereof will be hereinomitted.

Also, a part of the converted light signal 204 may enter another medium203 different from the scintillator 202, and a part of the convertedlight signal 204 may be condensed in a light receiving unit 205surrounded by the other medium 203. In this exemplary embodiment, toincrease an amount of the light signal 204 condensed in the lightreceiving unit 205, a shape of the scintillator 202 may be changed.

Referring to FIG. 3, the apparatus 300 of acquiring images created bypenetration of a radioactive ray according to the present exemplaryembodiment may be divided by a plurality of unit cells, and each of theunit cells may include a scintillator 302 and a light receiving unit306. The light signal condensed for each of the unit cells may beprocessed in the signal processing unit, and then restored to apenetration image.

The unit cells may be specifically described with reference to elements301 to 306.

An irradiated X-ray 301 may enter a side of the scintillator 302, andthe entered X-ray 301 may be converted into a light signal 304 in thescintillator 302. In this exemplary embodiment, the converted lightsignal may enter a medium 303 having a density different from a densityof the scintillator 302, and an advancing direction of the light signal304 may be changed. The medium 303 which will be hereinafter describedin detail may have a material type or an immaterial type. The medium 303of the material type may include at least one of elements includingNaI(Tl), CsI(Tl), LiI(Eu), ZnS(Ag), anthracene, plastics, and a liquid,and any element other than the above-mentioned elements may be used aslong as the element may change the advancing direction of the lightsignal.

Also, the medium 303 of the immaterial type may designate a vacuum orair, and may be understood as a space generated such that a side of thescintillator 302 is vacant as in a cavity, that is, the side thereof isdeformed.

First, when the medium 303 is understood as the vacuum or air, theadvancing direction of the light signal 304 may be changed according toa formed shape of the scintillator 302. Specifically, a side surface ofthe scintillator 302 adjacent to the light receiving unit 306 may beformed into a concave shape, so that the advancing direction of thelight signal generated inside the scintillator 302 is changed to adirection of the light receiving unit 306. According to the presentexemplary embodiment, the side surface of the scintillator 302 formedinto the concave shape may be as described above, however, any shape ofthe scintillator 302 capable of effectively condensing the light signalin the light receiving unit 306 may be used.

For another example, in a case of the medium 303 of the material type,the advancing direction of the generated light signal may be changed tothe direction of the light receiving unit 306 depending on a density ofthe medium 303 or the concave shape.

In cases of the medium 303 of material/immaterial types, a shape of themedium 303 may be laterally asymmetrical with respect to a location ofthe light receiving unit 306. This will be described in detail withreference to FIG. 4.

Referring to FIG. 4, in a scintillator 401, an angle Ø₁ between atangent line 403 and a line 404 in a specific part of a concave shape402 (or a second medium) with respect to an advancing direction 405 of acondensed X-ray and an angle Ø_(2′) between the line 404 and anadvancing direction 406 of the light signal generated due to the concaveshape 402 may be represented through Equation 1 below by Snell's law,which isN2*sin Ø₁ =N1*sin Ø₂,   [Equation 1]

wherein N1 represents a refractive index of a material used in theconcave shape 402, and N2 represents a refractive index of thescintillator 401. When Ø₂ is 70°, the refractive index of the concaveshape 402 is 1, and the refractive index of the scintillator 401 is 1.8,Ø₁ may be calculated as 32°. Consequently, the apparatus of acquiringimages created by penetration of a radioactive ray according to thepresent exemplary embodiment may condense light signals as much aspossible in the light receiving unit formed on a side of the apparatus.

The scintillator 401 may be formed into a circular arc shape, which islaterally symmetrical, when the light receiving unit, that is, acondensed point being located in a middle portion of the apparatus, anda side of the concave shape 402, as shown in FIG. 4, may be formed intoa deformed shape when the condensed point is positioned to one side.Also, a degree of the deformed shape of the concave shape 402 may bedetermined based on Equation 1.

FIG. 5 is a flowchart illustrating a method of acquiring images createdby penetration of a radioactive ray according to an exemplaryembodiment.

Referring to FIG. 5, the apparatus of acquiring images created bypenetration of a radioactive ray according to the present exemplaryembodiment may collect radioactive rays irradiated by a source inoperation S501, and generate a light signal in response to the collectedradioactive rays in operation S502. For this purpose, the apparatus mayinclude a medium for generating the light signal from the radioactiveray in terms of collecting an initial radioactive ray, and the mediummay include at least one of NaI(Tl), CsI(Tl), LiI(Eu), ZnS(Ag),anthracene, plastics, and a liquid. Also, in operation S503, theapparatus may change an advancing direction of the generated lightsignal, and condense the generated light signal in the light receivingunit. For this purpose, the apparatus may include another medium forchanging the advancing direction of the light signal. In this exemplaryembodiment, the other medium may have a specific gravity different fromthat of the medium for collecting the initial radioactive ray. Here, theother medium may include at least one of NaI(Tl), CsI(Tl), LiI(Eu),ZnS(Ag), anthracene, plastics, and a liquid, and also may be animmaterial type such as a vacuum state or the air. Specifically, anelement may be used as the other medium as long as the element is ableto change the advancing direction of the light signal through a reactionwith the light signal.

When the side of the medium collecting the initial radioactive ray isformed into a concave shape, the advancing direction of the light signalmay be changed to a direction of a light receiving sensor even withoutadditionally forming another medium. For an example, when a side surfaceof the medium, collecting the initial radioactive ray, adjacent to thelight receiving sensor is formed into the concave shape, the advancingdirection of the generated light signal may be changed to the directionof the light receiving sensor.

Even in this exemplary embodiment, the concave shape may be laterallyasymmetrical with respect to a location of the light receiving unit.

The light signal condensed in the light receiving sensor due to a changein a density may be converted into an electrical signal in operationS504, and the converted electrical signal is penetrated to an inspectiontarget to acquire a penetration image based on characteristics of thecollected radioactive rays in operation S505.

As described above, in the apparatus of acquiring images created bypenetration of a radioactive ray according to an exemplary embodiment, amajor part of the light signal generated from the irradiated radioactiveray may be used in acquiring images, thereby obtaining high qualityimages with a relatively high contrast. In addition, in the method ofacquiring images created by penetration of a radioactive ray accordingto an exemplary embodiment, penetration images of the inspection targetmay be obtained even using a relatively small amount of exposure,thereby reducing maintenance costs, and minimizing damage incurred bythe inspection target due to exposure of the radioactive ray. Also, onlythe shape of the scintillator may vary to change the advancing directionof the generated light signal to the direction of the light receivingsensor, thereby enabling design and embodiment of the apparatus at lowcosts.

The method of acquiring images created by penetration of a radioactiveray may be recorded, stored, or fixed in one or more computer-readablemedia that includes program instructions to be implemented by a computerto cause a processor to execute or perform the program instructions. Themedia may also include, alone or in combination with the programinstructions, data files, data structures, etc. The media and programinstructions may be those specially designed and constructed, or theymay be of the kind well-known and available to those having skill in thecomputer software arts. Examples of computer-readable media includemagnetic media such as hard disks, floppy disks, and magnetic tape;optical media such as CD ROM disks and DVDs; magneto-optical media suchas optical disks; and hardware devices that are specially configured tostore and perform program instructions, such as read-only memory (ROM),random access memory (RAM), flash memory, etc. The computer-readablemedia may also be a distributed network, so that the programinstructions are stored and executed in a distributed fashion. Theprogram instructions may be executed by one or more processors. Thecomputer-readable media may also be embodied in at least one applicationspecific integrated circuit (ASIC) or Field Programmable Gate Array(FPGA). Examples of program instructions include both machine code, suchas produced by a compiler, and files containing higher level code thatmay be executed by the computer using an interpreter. The describedhardware devices may be configured to act as one or more softwaremodules in order to perform the exemplary operations and methodsdescribed above, or vice versa.

Although a few exemplary embodiments have been shown and described, thepresent disclosure is not limited to the described exemplaryembodiments. Instead, it would be appreciated by those skilled in theart that changes may be made to these exemplary embodiments withoutdeparting from the principles and spirit of the disclosure, the scope ofwhich is defined by the claims and their equivalents.

What is claimed is:
 1. An apparatus of acquiring images created bypenetration of a radioactive ray, the apparatus comprising: ascintillator to generate a light signal in response to an irradiatedradioactive ray, and to change an advancing direction of the lightsignal; a light receiving unit to receive the light signal whoseadvancing direction is changed; and a signal processing unit to convertthe received light signal into an electrical signal, and acquire animage corresponding to the penetrated irradiated radioactive ray basedon the converted electrical signal, wherein the scintillator includes amedium having a density different from a density of the surrounding air,wherein the light signal from the scintillator enters another mediumdifferent from the medium of the scintillator before entering the lightreceiving unit, wherein the another medium surrounds at least threesides of the light receiving unit, and wherein a side surface of thescintillator adjacent to the light receiving unit is formed into aconcave shape, the concave shape being laterally asymmetrical withrespect to a location of the light receiving unit.
 2. The apparatus ofclaim 1, wherein the scintillator changes the advancing direction of thegenerated light signal to a direction of the light receiving unitaccording to a formed shape of the scintillator.
 3. The apparatus ofclaim 1, wherein the scintillator changes the advancing direction of thelight signal to a direction of the light receiving unit based on theconcave shape.
 4. The apparatus of claim 1, wherein another side surfaceof the scintillator is formed into a convex shape, wherein the anotherside surface is exposed to the irradiated radioactive ray.
 5. Theapparatus of claim 1, wherein the scintillator is formed in a circulararc shape.
 6. An apparatus of acquiring images created by penetration ofa radioactive ray, the apparatus comprising: a scintillator comprising afirst medium to generate a light signal and a second medium to change anadvancing direction of the light signal; a light receiving unit toreceive the light signal whose advancing direction is changed; and asignal processing unit to convert the received light signal into anelectrical signal, and acquire an image corresponding to the penetratedirradiated radioactive ray based on the converted electrical signal;wherein the second medium changes the advancing direction of the lightsignal towards a direction of the light receiving unit based on adifference between a density of the first medium and a density of thesecond medium, wherein the light signal from the scintillator entersanother medium different from the first medium and the second medium ofthe scintillator before entering the light receiving unit, wherein theanother medium surrounds at least three sides of the light receivingunit, and wherein a side surface of the first medium that contacts thesecond medium is formed into a concave shape, the concave shape beinglaterally asymmetrical with respect to a location of the light receivingunit.
 7. The apparatus of claim 6, wherein at least one of the firstmedium and the second medium includes at least one of NaI(Tl), CsI(Tl),LiI(Eu), ZnS(Ag), anthracene, plastics, and a liquid.
 8. The apparatusof claim 6, wherein the second medium is a gas or vacuum.